A. Field of the Invention
The impact sand anchor of the invention provides an anchor location in sand. As used in this document, the term ‘sand’ means beach sand and also means any other suitable soil or granular material into which the sand anchor may be driven. The sand anchor may support a beach umbrella, fishing rods, nets for game play or any other desired object on the sand. The impact sand anchor allows attachment of the beach umbrella or other object quickly and with little effort, making the impact sand anchor suitable for use by persons having limited strength. The impact sand anchor may be integral to a beach umbrella or other object to be supported. Alternatively, the impact sand anchor may be stand-alone. The Invention also relates to a method for supporting a beach umbrella using the impact sand anchor and a kit of parts including the impact sand anchor and a beach umbrella.
B. Statement of the Related Art
The simplest apparatus to support an umbrella on a beach or in other sandy soil is the bare pole of the umbrella. A user inserts the end of the bare pole in the sand to a suitable depth, say, 12 inches. The mass of the sand into which the bare pole is inserted and the friction force of the sand grains against one another resist blow-over of the bare pole and hence the umbrella. The friction force of the sand grains against the bare pole resists pull-out of the pole. As used in this document, the term ‘blow-over’ or ‘pull over’ refers to a force applied to a pole or umbrella generally parallel to the surface of the ground, as by a wind blowing normal to the longitudinal axis of the pole supporting the umbrella. As used in this document, the term ‘pull out’ refers to a force applied along the longitudinal axis of the pole in a direction away from the ground.
In a typical wind situation on a beach, a wind blows parallel to the surface of the ground and pushes upon an umbrella canopy supported by a bare umbrella pole. The umbrella pole is oriented initially so that its longitudinal axis is generally normal to the surface of the ground and to the wind. The force of the wind acting on the umbrella causes the umbrella pole to displace the sand into which the umbrella pole is buried, allowing the umbrella to tilt. As the umbrella pole tilts away from the wind, a component of the force applied by the wind to the umbrella canopy becomes a pull-out force along the longitudinal axis of the umbrella pole. For the same wind speed, the greater the tilt of the umbrella, the greater the pull-out force applied by the wind to the umbrella pole.
The resistance to pull-out of a partially buried bare pole is provided only by the friction of the sand grains against the buried shaft of the pole, and hence a bare umbrella pole offers little pull-out resistance. If the wind is successful in pulling the umbrella from the sand, the umbrella and its pole may tumble downwind, creating a hazard to the user and to others.
Sand anchors are known in the art. A prior art plate-type sand anchor may consist of plates, boards or logs buried in the sand and to which a guy line is attached. The plate-type sand anchor may support a tube, such as a tube to receive the end of an umbrella pole. The plate, boards or log must be buried in a hole that is large enough to receive the plate, board or log and deep enough so that the weight of sand on the top of the plate, board or log will adequately apply tension to the guy line or will adequately support the tube. The user must manually dig and fill the hole, which may not be possible for persons having limited strength or endurance.
A tapered thread-type sand anchor includes a tapered shaft having a threaded portion. The user turns the shaft to turn the threaded portion of the tapered thread-type sand anchor, engaging the threads with the sand to pull the sand anchor into the sand. Turning a tapered thread-type sand anchor can require considerable strength and work, placing use of such anchors out-of-reach by persons having limited strength or limited endurance. Rather than turning the shaft, many users may dig a hole in the sand and manually bury the threaded portion of the tapered thread-type sand anchor.
An auger-type sand anchor provides a propeller shape on the end of a tubular shaft. As for the tapered thread-type sand anchor, the user turns the tubular shaft and the propeller shape pulls the auger-type sand anchor into the sand. As for the tapered thread-type anchor, turning a auger-type sand anchor can require considerable strength and work, placing use of such anchors out-of-reach by persons having limited strength or limited endurance. Many users may dig a hole and manually bury auger-type sand anchors rather than attempt to install the anchor by turning the shaft.
An angled tube-type of sand anchor provides a thick-walled cylindrical plastic tube that is driven into the sand. The bottom end of the tube slopes from one side of the tube to the other, so that one side of the tube extends further in the downward direction than the other and providing a relatively sharp point on one side of the tube. In use, the sharp point is driven into the sand using a hammer. During installation, the hollow tube becomes plugged with sand, forming an asymmetrical wedge that forces the sand anchor laterally in response to hammer blows, reducing the contact of the angled tube with the sand and reducing its resistance to pull-out and pull-over. Removing sand packed into the end of the tube also can be a challenge and may require multiple hammer blows.
The prior art does not teach the sand anchor of the Invention.